Self-sealing, disposable, plastic storage bags are flexible, disposable plastic bags commonly used to temporarily store food, such as leftovers or sandwiches, or to place food, such as meats, in the freezer over a long period of time. These storage bags incorporate interlocking strips which extend across an open end of the bag. The interlocking strips include mateable male and female, or tongue and groove portions which interlock to close the open end of the bag. Examples include storage bags sold under the trademark ZIPLOC®, which is a registered trademark of SC Johnson & Son, Inc. and GLAD®, which is a registered trademark of the Glad Products Company. Self-sealing storage bags are primarily purchased in the consumer market for storing perishable foods.
Once contents are placed in the storage bag, the male and female strips are oriented, engaged, and pressed shut by applying pressure across the strips with the fingers or a slide mechanism. Conventional self-sealing bags, however, are not designed for conveniently evacuating air from the bag or for maintaining an airtight seal. Hence, food can still go stale or suffer freezer burn as a result of trapped air within the bag. This is because conventional self-sealing storage bags do not offer structure for evacuating air.
To evacuate air from inside the bag, users try to keep a segment of the bag open while pressing down on the bag to force air out. This process fails to remove all the air and is a crude, inconvenient way to evacuate air. Other users may attempt to use their mouth to suck air from the storage bag. This process also unable to remove all air, and risks contamination of the bag's contents with germs.
A significant problem associated with providing an airtight, self-sealing bag that evacuates air relates to manufacturing. Plastic storage bags are extruded and formed at a high speed which reduces production costs so that the storage bags can be marketed at a price point that is acceptable to consumers. High speed manufacturing processes make it difficult to alter the structure of the bag without affecting production and therefore increasing cost significantly. Existing processes and techniques for installing valve assemblies, for example, increase the cost of a storage bag to the point that it is no longer practical for disposable applications in which storage bags are commonly employed.
U.S. Pat. No. 5,240,112, issued to Neuberger, shows a storage bag with a stem with a pinched valve protruding outward from the lower end. U.S. Pat. No. 5,544,752, issued to Cox, shows storage bag that includes a permanent, exterior suction conduit that is designed to break off after use. U.S. Pat. No. 3,980,226, issued to Franz, comprises a storage bag having a permanently affixed evacuating tube with a threaded cap and an open end which is tied shut. U.S. Pat. No. 6,045,264 shows a system that attempts to improve on several of the deficiencies of earlier systems, but still requires that the bag itself be formed as a special-purpose evacuable bag. These systems are not compatible with existing extrusion manufacturing techniques.
Some of the more effective food storage systems use a “rolled bag” technique in which the user purchases a roll of material that is essentially a plastic channel, then forms bags by heat sealing two ends of the channel. These systems are often referred to as “seal-a-meal” systems as exemplified in U.S. Pat. No. 4,021,290. Variations of this system have been introduced that provide various mechanisms for removing air from the bag before sealing. These systems tend to be more expensive than disposable storage bags, and they are more difficult to use because the user is actually forming each bag one at a time.
A need exists for a food storage system that is both cost effective and allows users to evacuate air from commercially available self-sealing plastic storage bags.